The zonule of Zinn (Zinn's membrane, ciliary zonule) is a ring of fibrous strands connecting the ciliary body with the crystalline lens of the eye. The zonule of Zinn is split into two layers: a thin layer, which lines the hyaloid fossa, and a thicker layer, which is a collection of zonular fibers. Together, the fibers are known as the suspensory ligament of the lens[WP]. Modified or toughened vitreous that suspend the lens at the equator to the non-pigmented epithelium of the ciliary zone. In zebrafish, dorsal zonules are thickened as compared to ventral zonules. In both dorsal and ventral regions, these fibers delimit the vitreous body aqueous humor boundary[ZFA].